The invention is in the field of manufacturing container bodies, and in particular can bodies made of sheet steel. During the production thereof, individual sheets are destacked from a stack and fed to a rounding device, and subsequently to a welding machine for welding the longitudinal seam of the container or of the can. This is known to the person skilled in the art. The stack composed of individual sheets located on top of one another, which comprises approximately 200 to 1000 sheets, for example, is located in a stacking magazine and is seated there on laterally provided support rails and support detents, so that the weight of the stack acts on the lowest sheet. According to the prior art, the lowest sheet is contacted by a drivably upward and downward moving suction head having multiple suction cups in the upper position of the suction head and is attracted to the head using negative pressure. During the downward movement of the suction head, the attracted sheet is pulled away downward and out of the support rails and support detents. As the sheet is removed, air must flow into the region between the lowest sheet to be extracted and the remaining sheet stack so as to compensate for the negative pressure between the lowest and the second lowest sheets which develops during removal. Otherwise multiple sheets are destacked simultaneously, which results in undesirable disruptions and in production downtime and material losses. So as to support the separation of the lowest sheet from the remaining sheet stack, separating air is blown in via air nozzles provided laterally in the stacking magazine. The air film thus formed between the lowest few sheets assures that ambient air flows in and separates the lowest sheet from the second lowest sheet during extraction. If high production speeds are to be achieved, separating air during destacking is indispensable. A high production speed is considered to be a range of 200 sheets per minute to 1200 sheets per minute. Typically, processes operate at 600 sheets per minute.
It has been shown that destacking becomes problematic in the above-described conventional manner with thin sheets (which is considered to include metal sheets having a thickness of less than 0.14 mm), and in particular with square sheet formats, in which the path for air to flow in from all sides is long. The separating air is poorly suited for thin sheets since these metal sheets are not sufficiently stable and may fall downward out of the stacking magazine as a result of the use of the separating air.